Lecture 2

Question 1

Get identifier of an object a, test equality of a and b

Answer 1

id(a), a is b

Question 2

Immutable objects

Answer 2

tuples, strings, floats, ints (a[2]=… returns an error!)

Question 3

Mutable objects

Answer 3

lists, dictionaries

Question 4

Indexing

Answer 4

a[i:j:k], start, stop (not included), step

Question 5

Copy a list a

Answer 5

a.copy()

Question 6

John = 'computer_science'
   Tim = John
   Tim += ', math'
   Anna = ['electrical']
   Julie = Anna
   Julie += ['physics']
   print(John, Anna)

Answer 6

computer_science [‘electrical’, ‘physics’]

Question 7

A = [1,2,3,4]
B = A
C = A

B.append(5)
C = C + [6]
B.append(6)

Answer 7

A==B==C

A is B but A is not C!

Question 8

Pop method?

Answer 8

A.pop(i) returns the ie element of the list and removes it.

Question 9

Modify a list inside a function

Answer 9

list[:] = …

Question 10

Loop on index, value

Answer 10

for i, v in enumerate(a)

Question 11

Loop on key, value (dictionary)

Answer 11

for k, v in a.items()

Question 12

Lowercase a string

Answer 12

a.lower()

Question 13

Apply a function to each element of a list

Answer 13

list(map(fct, a))

Question 14

Split a string into list of words

Answer 14

a.split()

Question 15

Create list of tuples from two lists

Answer 15

list(zip(a1, a2))

Question 16

Sort a list (ordering function and direction…)

Answer 16

a.sort(key=lambda x: x[i], reverse=True)